DIRECTION OF BULLET A KEY ISSUE IN JEAN HARRIS MURDER TRIAL

By JAMES FERON, Special to the New York Times

Published: January 22, 1981

WHITE PLAINS, Jan. 21—
A pathologist testifying for the defense in the Jean S. Harris murder trial said today that the ''irregular'' shaped bullet wound in Dr. Herman Tarnower's chest could have been caused by the bullet's ''changing direction'' as it hit a collarbone.

The chest wound, one of several, has become a key element in the 10-week-old trial. The prosecution has said the bullet first pierced one of the doctor's hands ''held in a defensive position,'' as one prosecution witness put it, while the defense has said the chest and hand wounds were incurred separately.

The pathologist, Dr. Cyril H. Wecht, conceded earlier under crossexamination by the prosecutor, George Bolen, that the chest wound was the only one sustained last March 10 by Dr. Tarnower that was not symmetrical in shape and that it could have been caused by the bullet having hit something else first.

Such a ''ricochet,'' Mr. Bolen sought to demonstrate, could have been caused by the bullet having gone through the cardiologist's hand, held palm outward, before entering his chest. The doctor suffered such a wound and the so-called defensive posture would be consistent with the charge that Mrs. Harris shot him in a jealous rage.

Dr. Wecht said it was ''a possibility'' that the bullet went through the hand first, but he said he saw no reason for it to have been ''tumbling,'' as Mr. Bolen put it, when it hit the chest. He was asked how he would explain the irregularity of the wound.

The bullet, he said, ''could have struck at a 90-degree angle, striking the skin over the clavicle. Even before going completely through the skin, it may already have changed direction.'' Bullet Held Not Deflected

Mrs. Harris's lawyer, Joel Aurnou, then gave the pathologist an opportunity to diminish further the prosecution theory. ''Does the perfectly circular wound in the back of the hand tell you anything?'' Mr. Aurnou asked. Dr. Wecht, a former medical examiner for Allegheny County in Pennsylvania, said it meant the bullet ''went through the hand in a straight line, without deflection, and emerged in a straight path. It would not be tumbling or yawing.''

Mr. Bolen asked Dr. Wecht if he still felt he could not rule out a struggle as having occurred between Mrs. Harris, a former headmistress at a Virginia school for girls, and Dr. Tarnower, her companion for 14 years.

''I said the likelihood was more probable than not,'' the witness replied. The prosecutor asked Dr. Wecht if he held to that view after considering that the doctor was 5 feet 10 inches tall and weighed 175 pounds while Mrs. Harris was 5 feet 4 inches and 105 pounds.

''Yes,'' the witness said. Mr. Bolen offered other reasons that made him feel there was no struggle, including that ''no furniture had been knocked over.'' Mrs. Harris, listening intently, laughed at this observation while Dr. Wecht recalled that ''there was a broken window - something had been hurled at it.''